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Annals of Botany Sep 2020With limited agricultural land and increasing human population, it is essential to enhance overall photosynthesis and thus productivity. Oxygenic photosynthesis begins... (Review)
Review
BACKGROUND
With limited agricultural land and increasing human population, it is essential to enhance overall photosynthesis and thus productivity. Oxygenic photosynthesis begins with light absorption, followed by excitation energy transfer to the reaction centres, primary photochemistry, electron and proton transport, NADPH and ATP synthesis, and then CO2 fixation (Calvin-Benson cycle, as well as Hatch-Slack cycle). Here we cover some of the discoveries related to this process, such as the existence of two light reactions and two photosystems connected by an electron transport 'chain' (the Z-scheme), chemiosmotic hypothesis for ATP synthesis, water oxidation clock for oxygen evolution, steps for carbon fixation, and finally the diverse mechanisms of regulatory processes, such as 'state transitions' and 'non-photochemical quenching' of the excited state of chlorophyll a.
SCOPE
In this review, we emphasize that mathematical modelling is a highly valuable tool in understanding and making predictions regarding photosynthesis. Different mathematical models have been used to examine current theories on diverse photosynthetic processes; these have been validated through simulation(s) of available experimental data, such as chlorophyll a fluorescence induction, measured with fluorometers using continuous (or modulated) exciting light, and absorbance changes at 820 nm (ΔA820) related to redox changes in P700, the reaction centre of photosystem I.
CONCLUSIONS
We highlight here the important role of modelling in deciphering and untangling complex photosynthesis processes taking place simultaneously, as well as in predicting possible ways to obtain higher biomass and productivity in plants, algae and cyanobacteria.
Topics: Biomass; Chlorophyll; Chlorophyll A; Electron Transport; Humans; Light; Oxygen; Photosynthesis; Photosystem II Protein Complex; Water
PubMed: 31641747
DOI: 10.1093/aob/mcz171 -
Molecules (Basel, Switzerland) May 2020Plants contain abundant autofluorescent molecules that can be used for biochemical, physiological, or imaging studies. The two most studied molecules are chlorophyll... (Review)
Review
Plants contain abundant autofluorescent molecules that can be used for biochemical, physiological, or imaging studies. The two most studied molecules are chlorophyll (orange/red fluorescence) and lignin (blue/green fluorescence). Chlorophyll fluorescence is used to measure the physiological state of plants using handheld devices that can measure photosynthesis, linear electron flux, and CO assimilation by directly scanning leaves, or by using reconnaissance imaging from a drone, an aircraft or a satellite. Lignin fluorescence can be used in imaging studies of wood for phenotyping of genetic variants in order to evaluate reaction wood formation, assess chemical modification of wood, and study fundamental cell wall properties using Förster Resonant Energy Transfer (FRET) and other methods. Many other fluorescent molecules have been characterized both within the protoplast and as components of cell walls. Such molecules have fluorescence emissions across the visible spectrum and can potentially be differentiated by spectral imaging or by evaluating their response to change in pH (ferulates) or chemicals such as Naturstoff reagent (flavonoids). Induced autofluorescence using glutaraldehyde fixation has been used to enable imaging of proteins/organelles in the cell protoplast and to allow fluorescence imaging of fungal mycelium.
Topics: Cell Wall; Chlorophyll; Fluorescence; Fluorescence Resonance Energy Transfer; Green Fluorescent Proteins; Lignin; Luminescent Proteins; Plant Leaves; Plants
PubMed: 32455605
DOI: 10.3390/molecules25102393 -
Current Biology : CB Jan 2021Tracy Ainsworth and Barbara Brown introduce the causes and consequences of coral bleaching.
Tracy Ainsworth and Barbara Brown introduce the causes and consequences of coral bleaching.
Topics: Animals; Anthozoa; Chlorophyll; Color; Conservation of Natural Resources; Coral Reefs; Dinoflagellida; Global Warming; Hot Temperature; Photobleaching; Symbiosis
PubMed: 33434489
DOI: 10.1016/j.cub.2020.10.048 -
Biomolecules Jul 2021Chlorophyllides can be found in photosynthetic organisms. Generally, chlorophyllides have -, -, -, -, and -type derivatives, and all chlorophyllides have a tetrapyrrole... (Review)
Review
Chlorophyllides can be found in photosynthetic organisms. Generally, chlorophyllides have -, -, -, -, and -type derivatives, and all chlorophyllides have a tetrapyrrole structure with a Mg ion at the center and a fifth isocyclic pentanone. Chlorophyllide can be synthesized from protochlorophyllide , divinyl chlorophyllide , or chlorophyll. In addition, chlorophyllide can be transformed into chlorophyllide , chlorophyllide , or chlorophyllide . Chlorophyllide can be synthesized from protochlorophyllide or divinyl protochlorophyllide . Chlorophyllides have been extensively used in food, medicine, and pharmaceutical applications. Furthermore, chlorophyllides exhibit many biological activities, such as anti-growth, antimicrobial, antiviral, antipathogenic, and antiproliferative activity. The photosensitivity of chlorophyllides that is applied in mercury electrodes and sensors were discussed. This article is the first detailed review dedicated specifically to chlorophyllides. Thus, this review aims to describe the definition of chlorophyllides, biosynthetic routes of chlorophyllides, purification of chlorophyllides, and applications of chlorophyllides.
Topics: Anti-Infective Agents; Antineoplastic Agents, Phytogenic; Antiviral Agents; Biosensing Techniques; Chemistry, Pharmaceutical; Chlorophyll; Chlorophyllides; Electrochemical Techniques; Food Additives; Humans; Light; Molecular Structure; Photosynthesis; Plants; Protochlorophyllide
PubMed: 34439782
DOI: 10.3390/biom11081115 -
Molecules (Basel, Switzerland) Feb 2022Chlorophylls provide the basis for photosynthesis and thereby most life on Earth. Besides their involvement in primary charge separation in the reaction center, they...
Chlorophylls provide the basis for photosynthesis and thereby most life on Earth. Besides their involvement in primary charge separation in the reaction center, they serve as light-harvesting and light-sensing pigments, they also have additional functions, e.g., in inter-system electron transfer. Chlorophylls also have a wealth of applications in basic science, medicine, as colorants and, possibly, in optoelectronics. Considering that there has been more than 200 years of chlorophyll research, one would think that all has been said on these pigments. However, the opposite is true: ongoing research evidenced in this Special Issue brings together current work on chlorophylls and on their carotenoid counterparts. These introductory notes give a very brief and in part personal account of the history of chlorophyll research and applications, before concluding with a snapshot of this year's publications.
Topics: Carotenoids; Chlorophyll; Electron Transport; Energy Transfer; History, 19th Century; History, 20th Century; History, 21st Century; Humans; Light-Harvesting Protein Complexes; Photosynthesis
PubMed: 35164358
DOI: 10.3390/molecules27031093 -
Marine Drugs May 2020Chlorophyll breakdown products are usually studied for their antioxidant and anti-inflammatory activities. The chlorophyll derivative Pheophorbide (PPB) is a... (Review)
Review
Chlorophyll breakdown products are usually studied for their antioxidant and anti-inflammatory activities. The chlorophyll derivative Pheophorbide (PPB) is a photosensitizer that can induce significant anti-proliferative effects in several human cancer cell lines. Cancer is a leading cause of death worldwide, accounting for about 9.6 million deaths, in 2018 alone. Hence, it is crucial to monitor emergent compounds that show significant anticancer activity and advance them into clinical trials. In this review, we analyze the anticancer activity of PPB with or without photodynamic therapy and also conjugated with or without other chemotherapic drugs, highlighting the capacity of PPB to overcome multidrug resistance We also report other activities of PPB and different pathways that it can activate, showing its possible applications for the treatment of human pathologies.
Topics: Antineoplastic Agents; Cell Line, Tumor; Chlorophyll; Humans
PubMed: 32423035
DOI: 10.3390/md18050257 -
Journal of the Royal Society, Interface Mar 2020It has long been recognized that visible light harvesting in Peridinin-Chlorophyll-Protein is driven by the interplay between the bright (S) and dark (S) states of...
It has long been recognized that visible light harvesting in Peridinin-Chlorophyll-Protein is driven by the interplay between the bright (S) and dark (S) states of peridinin (carotenoid), along with the lowest-lying bright (Q) and dark (Q) states of chlorophyll-. Here, we analyse a chromophore cluster in the crystal structure of Peridinin-Chlorophyll-Protein, in particular, a peridinin-peridinin and a peridinin-chlorophyll- dimer, and present quantum chemical evidence for excited states that exist beyond the confines of single peridinin and chlorophyll chromophores. These dark multichromophoric states, emanating from the intermolecular packing native to Peridinin-Chlorophyll-Protein, include a correlated triplet pair comprising neighbouring peridinin excitations and a charge-transfer interaction between peridinin and the adjacent chlorophyll-. We surmise that such dark multichromophoric states may explain two spectral mysteries in light-harvesting pigments: the sub-200-fs singlet fission observed in carotenoid aggregates, and the sub-200-fs chlorophyll- hole generation in Peridinin-Chlorophyll-Protein.
Topics: Carotenoids; Chlorophyll; Chlorophyll A; Proteins
PubMed: 32183641
DOI: 10.1098/rsif.2019.0736 -
Sensors (Basel, Switzerland) Jul 2019Measuring chlorophyll fluorescence is a direct and non-destructive way to monitor vegetation. In this paper, the fluorescence retrieval methods from multiple scales,... (Review)
Review
Measuring chlorophyll fluorescence is a direct and non-destructive way to monitor vegetation. In this paper, the fluorescence retrieval methods from multiple scales, ranging from near the ground to the use of space-borne sensors, are analyzed and summarized in detail. At the leaf-scale, the chlorophyll fluorescence is measured using active and passive technology. Active remote sensing technology uses a fluorimeter to measure the chlorophyll fluorescence, and passive remote sensing technology mainly depends on the sun-induced chlorophyll fluorescence filling in the Fraunhofer lines or oxygen absorptions bands. Based on these retrieval principles, many retrieval methods have been developed, including the radiance-based methods and the reflectance-based methods near the ground, as well as physically and statistically-based methods that make use of satellite data. The advantages and disadvantages of different approaches for sun-induced chlorophyll fluorescence retrieval are compared and the key issues of the current sun-induced chlorophyll fluorescence retrieval algorithms are discussed. Finally, conclusions and key problems are proposed for the future research.
Topics: Algorithms; Atmosphere; Chlorophyll; Fluorescence; Models, Statistical; Models, Theoretical; Plant Leaves; Remote Sensing Technology; Spacecraft; Spectrophotometry
PubMed: 31288380
DOI: 10.3390/s19133000 -
International Journal of Molecular... Aug 2021Magnetopriming has emerged as a promising seed-priming method, improving seed vigor, plant performance and productivity under both normal and stressed conditions.... (Review)
Review
Magnetopriming has emerged as a promising seed-priming method, improving seed vigor, plant performance and productivity under both normal and stressed conditions. Various recent reports have demonstrated that improved photosynthesis can lead to higher biomass accumulation and overall crop yield. The major focus of the present review is magnetopriming-based, improved growth parameters, which ultimately favor increased photosynthetic performance. The plants originating from magnetoprimed seeds showed increased plant height, leaf area, fresh weight, thick midrib and minor veins. Similarly, chlorophyll and carotenoid contents, efficiency of PSII, quantum yield of electron transport, stomatal conductance, and activities of carbonic anhydrase (CA), Rubisco and PEP-carboxylase enzymes are enhanced with magnetopriming of the seeds. In addition, a higher fluorescence yield at the J-I-P phase in polyphasic chlorophyll a fluorescence (OJIP) transient curves was observed in plants originating from magnetoprimed seeds. Here, we have presented an overview of available studies supporting the magnetopriming-based improvement of various parameters determining the photosynthetic performance of crop plants, which consequently increases crop yield. Additionally, we suggest the need for more in-depth molecular analysis in the future to shed light upon hidden regulatory mechanisms involved in magnetopriming-based, improved photosynthetic performance.
Topics: Chlorophyll; Fluorescence; Magnetic Fields; Photosynthesis; Plant Leaves; Plant Proteins; Plants; Seeds
PubMed: 34502258
DOI: 10.3390/ijms22179353 -
Journal of Experimental Botany Aug 2022Tetrapyrrole biosynthesis produces metabolites that are essential for critical reactions in photosynthetic organisms, including chlorophylls, heme, siroheme,... (Review)
Review
Tetrapyrrole biosynthesis produces metabolites that are essential for critical reactions in photosynthetic organisms, including chlorophylls, heme, siroheme, phytochromobilins, and their derivatives. Due to the paramount importance of tetrapyrroles, a better understanding of the complex regulation of tetrapyrrole biosynthesis promises to improve plant productivity in the context of global climate change. Tetrapyrrole biosynthesis is known to be controlled at multiple levels-transcriptional, translational and post-translational. This review addresses recent advances in our knowledge of the post-translational regulation of tetrapyrrole biosynthesis and summarizes the regulatory functions of the various auxiliary factors involved. Intriguingly, the post-translational network features three prominent metabolic checkpoints, located at the steps of (i) 5-aminolevulinic acid synthesis (the rate-limiting step in the pathway), (ii) the branchpoint between chlorophyll and heme synthesis, and (iii) the light-dependent enzyme protochlorophyllide oxidoreductase. The regulation of protein stability, enzymatic activity, and the spatial organization of the committed enzymes in these three steps ensures the appropriate flow of metabolites through the tetrapyrrole biosynthesis pathway during photoperiodic growth. In addition, we offer perspectives on currently open questions for future research on tetrapyrrole biosynthesis.
Topics: Chlorophyll; Heme; Photosynthesis; Plants; Tetrapyrroles
PubMed: 35536687
DOI: 10.1093/jxb/erac203